Examples of a single site catalyst for polymerizing an addition polymerizable monomer such as an olefin are:
(1) a catalyst using a combination of bis(cyclopentadienyl)zirconium dichloride with methylaluminoxane (JP 58-19309A),
(2) a catalyst using a combination of bis(cyclopentadienyl)zirconium dichloride with a specific boron compound (JP 58-19309A),
(3) a catalyst using a combination of bis(cyclopentadienyl)zirconium dimethyl with tri(n-butyl)ammonium tetraxis(pentafluorophenyl)borate (JP 1-502036W),
(4) a single site catalyst, which lowers slightly homogeneity of an addition polymer obtained (JP 5-320248A, JP 10-17617A, JP 11-12319A and JP 11-343306A), and
(5) a catalyst using a specific particle as one of catalyst components (JP 61-296008A and JP 9-249707A).
However, these single site catalysts cannot produce an addition polymer having a satisfactorily high molecular weight in addition polymerized particle-producing polymerization such as slurry polymerization, gas phase polymerization and bulk polymerization. Here, the term “addition polymerized particle-producing polymerization” means polymerization producing a polymer particle by polymerizing an addition polymerizable monomer.